3 Aug
2009
3 Aug
'09
2:39 a.m.
Hi.
Josh Dersch <derschjo at mail.msu.edu> wrote:
I'm still trying to figure out what's gone
wrong with the unibus on my
11/40. To recap -- the machine is responsive if I run it without a
terminator at the end of the bus; with a terminator installed the front
panel is unresponsive. I've checked the following:
- The NPG grants are continuous from the front to the back.
- There are grant continuity cards in each empty slot.
- I am running with a minimal configuration (only CPU and 64K MOS memory)
I made one final discovery about two months ago -- the SPC slot in slot
9 of the main CPU backplane (which I am 100% sure is an SPC slot and not
some special-purpose slot) does not work properly. I cannot get the
Console SLU/LTC board to function when installed in slot 9 (which is
where it's typically installed, or so I hear). It works fine in other
unibus slots.
That is not a good sign.
I have three questions, any help on these would be,
well... helpful.
I'm hoping to have some time to play around with it in the coming months.
1) Is the NPG grant on the SPC slot on the processor backplane (slot 9)
supposed to be connected to the NPG grants on the Unibus expansion?
That is -- right now if I set my DMM to continuity mode and put one
probe on CA1 on the first slot of the unibus expansion, and the other on
CB1 on the last slot of the unibus expansion, since all NPG grant
jumpers are in place, the DMM shows the circuit as closed. This is as
I'd expect. However, if I move the probe from CA1 on the first slot of
the expansion to CA1 on slot 9 of the processor backplane, the circuit
is then open. I'm guessing this is not correct. (There is currently an
NPG jumper installed on slot 9.) All other grant lines seem to be
continuous.
That sounds really bad. NPG should originate from the CPU (unless my
memory fails me), and pass through each SPC slot. If it don't even make
it to the first slot (slot 09 of the CPU box) then you'll never get a
working system.
But how can you have a connection from CB1 out from the CPU slot 9, but
not a connection from CA1 out, when you do have a jumper between CA1 and
CB1 (of slot 9)? That sounds like a broken jumper to me.
2) Where is the +15V to the processor backplane
supposed to be
connected? (I suspect this may be the reason the SLU won't function in
slot 9...). Right now it's plugged into pin CV1 on slot 9 (if I'm
reading the Unibus pin chart right :)) but the docs I have found say
this should be ACLO_L...
Have you measured? Is it +15V, or +5V? ACLO_L is active low, and if you
have a good AC in, then I would expect that pin to be +5V in that case.
Afraid I can't help more right now. Any description of an SPC slot
should tell you, but I'm not sitting next to any manuals right now.
3) Does anyone have a wirelist for the 11/40 CPU
backplane (or is this
in any of the service/reference manuals)? Worst case, I can probe out
the wiring and figure out what's missing/incorrect on slot 9.
Sorry that I can't help more on this one. Didn't see any on bitsavers.
Maybe someone else have them?
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
4 Aug
4 Aug
11:40 a.m.
Date: Mon, 3 Aug 2009 11:39:28 +0200
From: bqt at softjar.se
To: cctalk at classiccmp.org
Subject: Re: Re-request for 11/40 unibus clarification...
Hi.
Josh Dersch wrote:
[...snip...]
> 3) Does anyone have a wirelist for the 11/40 CPU
backplane
> (or is this in any of the service/reference manuals)?
> Worst case, I can probe out the wiring and figure out
> what's missing/incorrect on slot 9.
I had a look at bitsavers and was a bit surprised to see
that none of the 11/40 (11/35) engineering drawings or
field maintenance print sets are available there!
I needed some time to localize my 11/40 documentation ...
I have two sets of the engineering drawings of the 11/40,
one contains the KD11-A backplane wire list rev. C, the other
has rev. F. The set of course has the 11/40 CPU boards, and
also stack limit, line time clock, power harness, the workz.
The wire list is 17 pages (33 sides), Ledger format. I could
scan them given a few days (tomorrow I have a day off).
Can you look at the label / sticker on the side of the 11/40
backplane? Maybe it says which Rev it is. I don't know the
differences between rev. C and rev F.
- Henk
www.pdp-11.nl
3:43 p.m.
Henk Gooijen wrote:
I had a look at bitsavers and was a bit surprised to
see
that none of the 11/40 (11/35) engineering drawings or
field maintenance print sets are available there!
I know there is a version of the printset online because I found it. I
think I have the link at work.
The link was www.classicon.org or something close to that.
-chuck
9:53 p.m.
Henk Gooijen wrote:
I had a look at bitsavers and was a bit surprised to see
that none of the 11/40 (11/35) engineering drawings or
field maintenance print sets are available there!
I needed some time to localize my 11/40 documentation ...
I have two sets of the engineering drawings of the 11/40,
one contains the KD11-A backplane wire list rev. C, the other
has rev. F. The set of course has the 11/40 CPU boards, and
also stack limit, line time clock, power harness, the workz.
The wire list is 17 pages (33 sides), Ledger format. I could
scan them given a few days (tomorrow I have a day off).
Can you look at the label / sticker on the side of the 11/40
backplane? Maybe it says which Rev it is. I don't know the
differences between rev. C and rev F.
Thanks! (And thanks also to Al for putting up a set on Bitsavers --
downloading now.)
Looks like I have wire wrap Rev D on my backplane. Looks like the
Bitsavers copy is Rev F. I suppose the odds of anyone knowing what the
changes were between D and F are going to be pretty low :).
- Henk
www.pdp-11.nl
5 Aug
5 Aug
11:12 a.m.
Date: Tue, 4 Aug 2009 21:53:03 -0700
From: derschjo at mail.msu.edu
To:
Subject: Re: Re-request for 11/40 unibus clarification...
Henk Gooijen wrote:
Thanks (can't be said often enough) for making available Al!
Whatever the differences are between rev. F and your Rev. D backplane,
you will certainly be able to check the "non-UNIBUS-ness" of slot 9 ...
gd luck,
- Henk.
[...snip...]
The wire list is 17 pages (33 sides), Ledger format. I could
scan them given a few days (tomorrow I have a day off).
Can you look at the label / sticker on the side of the 11/40
backplane? Maybe it says which Rev it is. I don't know the
differences between rev. C and rev F.
Thanks! (And thanks also to Al for putting up a set on Bitsavers --
downloading now.)
Looks like I have wire wrap Rev D on my backplane. Looks like the
Bitsavers copy is Rev F. I suppose the odds of anyone knowing what the
changes were between D and F are going to be pretty low :).
7 Aug
7 Aug
1:38 a.m.
Henk Gooijen wrote:
Well, I spent the evening probing out the slot 9 wiring and double
checking it with the print set, and everything checked out a-ok. I was
really disappointed :). While I had the backplane out I took the time
to give the backplane a good thorough cleaning (contact cleaner + wiping
down the connectors with a bit of cardboard in the slots).
Still having the same problems. Alas. I suppose I could go back and
check for shorts/incorrect connections in the wire wrap for slot 9 but
I'll leave that for another night when I have a LOT more spare time as
that would involve a lot more probing :). I did at least manage to
confirm that the +15V to slot 9 does connect at CU1. (I had
mis-identified it as CV1 in my previous mail.)
This is quite frustrating. I just want some blinkenlights, is that too
much to ask? :)
- Josh
Date: Tue, 4
Aug 2009 21:53:03 -0700
From: derschjo at mail.msu.edu
To:
Subject: Re: Re-request for 11/40 unibus clarification...
Thanks! (And thanks also to Al for putting up a set on Bitsavers --
downloading now.)
Looks like I have wire wrap Rev D on my backplane. Looks like the
Bitsavers copy is Rev F. I suppose the odds of anyone knowing what the
changes were between D and F are going to be pretty low :).
Thanks (can't be said often enough) for making available Al!
Whatever the differences are between rev. F and your Rev. D backplane,
you will certainly be able to check the "non-UNIBUS-ness" of slot 9 ...
gd luck,
- Henk.
5616
days inactive
5620
days old
7 comments
5 participants
participants (5)
-
aek＠bitsavers.org -
bqt＠softjar.se -
chd_1＠nktelco.net -
derschjo＠mail.msu.edu -
henk.gooijen＠hotmail.com